Citation

Nardone R, Bergmann J, Kunz A, Caleri F, Seidl M, Tezzon F, Gerstenbrand F, Trinka E, Golaszewski SM. J. Neurotrauma 2011; 28(7): 1165-1171.

Affiliation

Franz Tappeiner Hospital, Neurology, Merano, Italy; raffaele.nardone@asbmeran-o.it.

Copyright

(Copyright © 2011, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2010.1748

PMID

21446790

Abstract

Although chronic sleepiness is common after head trauma, the cause remains unclear. Transcranial magnetic stimulation (TMS) represents an useful complementary approach in the study of sleep pathophysiology. We aimed to determine in this study whether post-traumatic sleep-wake disturbances (SWD) are associated with changes in excitability of the cerebral cortex. TMS was performed 3 months after mild to moderate traumatic brain injury (TBI) in 11 patients with subjective excessive daytime sleepiness (EDS; defined by the Epworth Sleepiness Scale ≥ 10), 12 patients with objective EDS (as defined by mean sleep latency < 5 on multiple sleep latency test), 11 patients with fatigue (defined by daytime tiredness without signs of subjective or objective EDS), 10 patients with post-traumatic hypersomnia "sensu strictu", and 14 control subjects. Measures of cortical excitability included central motor conduction time, resting motor threshold (RMT), short latency intracortical inhibition (SICI) and intracortical facilitation to paired-TMS. RMT was higher and SICI was more pronounced in the patients with objective EDS than in the control subjects. In the other patients all TMS parameters did not differ significantly from the controls. Similar to that reported in patients with narcolepsy, the cortical hypoexcitability may reflect the deficiency of the excitatory hypocretin/orexin-neurotransmitter system. These observations may provide new insights into the causes of chronic sleepiness in patients with TBI. A better understanding of the pathophysiology of post-traumatic SWD may also lead to better therapeutic strategies in these patients.

Language: en